Catheters are tube-like members inserted into the body for diagnostic or therapeutic reasons. One of the therapeutic procedures applicable to the present invention is known as percutaneous transluminal coronary angioplasty (PTCA). This procedure can be used, for example, to reduce arterial build-up of cholesterol fats or atherosclerotic plaque. Typically, a guidewire is threaded through the vascular system to the site of the stenosis and the catheter subsequently tracked over it to the stenosis. The balloon at the distal end of the catheter is then inflated causing the site of the stenosis to widen. After the balloon is deflated, the catheter is withdrawn over the guidewire and another catheter can be slid into place over it if necessary.
Catheters typically have a manifold at their proximal end. The manifold is y-shaped with one arm of the "Y" providing an entrance port for the guidewire and the other arm of the "Y" providing an entrance port for inflation liquids. The manifold typically interconnects with a Luer coupler on its proximal end. The Luer coupler provides a guidewire entry port and interfaces with the manifold's straight arm which receives the guidewire. Manifolds typically have one or more seals to provide the sealing necessary to hold pressure under balloon inflation and maintain vacuum under balloon deflation.
Prior art manifold designs use threaded parts or adhesives to structurally join components. With adhesively bonded seals, bonding dissimilar materials presents difficulties. Prior art designs using threaded parts or adhesively bonded parts must have tightly controlled, highly accurate molded parts. Such parts are expensive to manufacture. What is needed is a seal which will eliminate the need for such tight tolerances, thereby reducing manufacturing time and expense.
Catheters are typically used in darkened environments to permit the physician to use fluoroscopy to monitor the movement of the balloon through the vascular system, the balloon having a radiopaque marker band. What is needed is a manifold which will be visible to the physician in a darkened laboratory during the PTCA procedure.
U.S. Pat. No. 5,129,887 to Euteneuer et al. for "Adjustable Manifold for Dilatation Catheter" discloses a threaded means 50/52, 125/126 and 160/170 for compressing seals 70, 134 and 168 in FIGS. 5, 6 and 7 respectively. For example, compression seal 70 is described at col. 5, lines 22-28 as being "a generally cylindrical resilient member having an outside diameter to fit within the wide interior passage 54B of cap 28, and having a central aperture 72 sized to receive outer tubing 14, which extends therethrough. One end of seal 70 abuts against distal end 30 of the inflation manifold 24, and the other end engages flange 66A of strain relief 66 against the flat side of washer 68". When cap 28 is screwed more tightly onto inflation manifold 24, this causes pressure on compression seal 70 which deforms (radially inwardly) to press outer member 14 against hypotube 64 with sufficient pressure that it is effectively locked in place by frictional forces. See col. 5, lines 32-37.
U.S. Pat. No. 4,838,269 to Robinson et al. for "Manifold for Angioplasty Balloon Catheter" discloses a threaded means of compressing a seal. "By rotation of the valve nut 110, sealing or unsealing of the compression or wire sealing O-ring 270 against a guide wire may be achieved". See col. 5, lines 38-40.
U.S. Pat. No. 4,842,592 to Caggiani et al. for "Connector Assembly" discloses a compression plug 6 within cavity 35, which compression causes constriction of the channel 38 and thereby secures the catheter 1 within the connector assembly 3. See col. 6, lines 47-50.
U.S. Pat. No. 5,203,774 to Gilson et al. for "Device for use with a Catheter" discloses a Touhy-Borst connector which "closes onto the external diameter of a sleeve, thus creating a seal between the Tuohy-Borst connector without impairing freedom of movement of the catheter within the sleeve". See col. 1, lines 59-62.
An object of the present invention is to provide a manifold which eliminates the need for adhesive seals and threaded parts with tight tolerances on molded parts. Another object of the invention is to provide a manifold which is visible in a darkened laboratory.